The present exemplary embodiment relates to controlling pressure systems. It finds particular application in conjunction with control arrangements for controlling pressure in pneumatically operated vehicle system, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications.
Air brake systems installed on large vehicles typically utilize pressurized air to operate the brakes of the vehicle. Prior art air brake systems usually include a combination of three different braking systems, namely: the service brakes, the parking brakes, and the emergency brakes. The service brake system applies and releases the brakes when the driver uses the brake pedal during normal driving situations. The parking brake system applies and releases the parking brakes when the parking brake control is actuated. The emergency brake system utilizes portions of the service brake and may use the parking brake systems to stop the vehicle in the event of a brake system failure.
In most air brake systems, when the driver or vehicle operator applies the service brakes by depressing the brake pedal, pressurized air passes through the brake pedal, through a series of valves, and enters the brake chambers to apply the brakes. When the driver or operator releases the brake pedal, the air pressure in the brake chambers is released, thereby de-actuating the service brakes.
Existing and future federal regulations may require both i) a certain amount of braking torque to be developed by the braking system within a prescribed period of time, and ii) specify maximum vehicle stopping distances. To comply with these regulations, and in an attempt to otherwise provide the most effective braking possible, conventional brake systems are generally configured to provide up to a maximum braking power as quickly as possible when requested by a vehicle operator. In the event of wheel lockup, the vehicle's anti-lock brake system (ABS) activates and modulates the application of the vehicle's brakes to unlock the wheels.